It is known that chlorine dioxide is formed by reaction of sodium chlorite and an acid. Thus, U.S. Pat. No. 3,591,515 to Lovely teaches the use of various acidifying agents to generate chlorine dioxide at a pH of less than 6. According to Lovely, a dry chlorine dioxide-yielding compound in powder form may be made by adsorbing a stabilized chlorine dioxide onto a basic-reacting adsorbent. The pulverized material is used to inhibit fungus growth in produce during shipment. U.S. Pat. No. 4,330,531 to Alliger discloses two-compartment containers for generating chlorine dioxide by reaction with an aqueous lactic acid solution. Thus, a syringe having two chambers separated by a common wall is shown, one chamber containing a sodium chlorite solution and the other chamber containing the lactic acid solution. Depressing the plunger simultaneously expels the solutions of each chamber. FIG. 4 in Alliger '531 illustrates a squeezable vial with two frangible containers therein, one container containing a sodium chlorite solution and the other containing a lactic acid solution. The vial has a cotton swab dauber in its outlet. FIG. 8 of '531 illustrates a plastic container crimped at about its midsection to form two chambers, one of which contains the chlorite solution and the other of which contains the acid solution. Removal of the crimp permits intermixing of the solutions.
U.S. Pat. No. 4,585,482 to Tice, et al. discloses a long-acting biocidal composition comprising a chlorine dioxide-liberating compound and sufficient hydrolyzable organic acid-generating polymer to lower the pH of the composition to less than about 7, the organic acid-generating polymer being present in a form whereby it is released gradually in the presence of water. The polymer is, for example, a methylvinylether/maleic anhydride copolymer.
None of the cited references disclose the formation of chlorine dioxide gas in a manner that takes advantage of its gaseous nature.
It has been found that the release of chlorine dioxide from its aqueous solution may be hastened and enhanced by generating the chlorine dioxide on an absorbent carrier. This allows the wicking action of the carrier to withdraw water from the aqueous system after the ClO.sub.2 has been formed, following which the ClO.sub.2 is emitted to the atmosphere.
It is an object of the present invention to provide an article of manufacture suitable to safely release chlorine dioxide to the atmosphere.
It is a primary object of the present invention to release chlorine dioxide by reacting a solution of sodium chlorite with an acid in dry form that has been impregnated into an absorbent carrier.
It is another object of this invention to provide chemical means in the absorbent carrier to accelerate the release of chlorine dioxide.
These and other objects and advantages of the present invention are set forth in the detailed description of the invention, a summary of which follows.